Collaborative Research: Photochemical Silicon Aerosols: Establishing Atmospheric Sources and Significance

本研究的重点是提高对挥发性甲基硅氧烷（VMS）在大气中的化学和物理转化的认识。挥发性甲基硅氧烷（VMS）是一种高产量化学品，用于许多个人护理产品，如除臭剂和乳液。预计这项研究的结果将导致更好地评估命运和运输问题，这对了解日益增加的VMS使用对环境和健康的影响至关重要。该项目的目的是评估实验室和环境大气气溶胶中氧化VMS的化学形态和丰度。该研究预计将确认由环境有机硅化合物形成的颗粒的存在，确定在城市和偏远氧化条件下近环境条件下的气溶胶产量，确定这类二次有机气溶胶的最佳气溶胶示踪化合物。并将这一努力的结果整合到一个最先进的光化学网格模型中，该模型将能够预测从城市大气到大陆范围内氧化后VMS的命运。本研究包括在爱荷华大学使用氧化流动反应器（OFR）进行的实验室研究和在科罗拉多大学环境室进行的实验，以探测VMS的氧化化学。VMS及其气相和冷凝相氧化产品的室外环境采样将在纽约市区进行为期四周的夏季部署。从这项研究中获得的科学见解将被纳入社区多尺度空气质量（CMAQ）建模系统，该系统将更好地预测个人护理产品产生的气溶胶。该项目由美国国家科学基金会大气化学计划和促进竞争性研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This research is focused on improving the understanding of the chemical and physical transformations of volatile methyl siloxanes (VMS) in the atmosphere. Volatile methyl siloxanes (VMS) are high production chemicals used in many personal care products such as deodorants and lotions. The results of this research are expected to lead to a better assessment of the fate and transport issues important for understanding the environmental and health consequences of the increasing use of VMS.The objective of this project is to assess the chemical speciation and abundance of oxidized VMS in the laboratory and in ambient atmospheric aerosols. This research is expected to confirm the presence of particles formed from ambient organosilicon compounds, establish aerosol yields at near-ambient conditions under urban and remote oxidation conditions, determine the best aerosol tracer compounds for this class of secondary organic aerosols, and integrate the results of this effort into a state-of-science photochemical grid model that will enable the prediction of the fate of VMS upon oxidation at scales ranging from urban airshed to continental.This research includes laboratory studies at the University of Iowa using an oxidative flow reactor (OFR) and experiments in the University of Colorado environmental chambers to probe the oxidation chemistry of VMS. Outdoor ambient sampling for VMS and its gas- and condensed-phase oxidation products will be conducted during a four-week summertime deployment in the New York City metropolitan area. The scientific insights gained from this research will be incorporated into the Community Multiscale Air Quality (CMAQ) modeling system that will lead to better predictions of aerosol formation from personal care products.This project is jointly funded by the NSF Atmospheric Chemistry Program and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.